Doodle, from James Hurst's short story The Scarlet Ibis, can be symbolized by many different things. Given that you are not allowed to use anything from the novel, and the text is very specific about symbolism and Doodle, your world of choices is actually very open to different symbols.

Here are some suggestions:

1. Doodle is "broken." It is stated at the very beginning when the narrator states that his father has already made him a coffin. Therefore, a broken toy could symbolize him based upon his age and the fact that he is "broken" himself.

2. Doodle could also be represented by a butterfly. The symbol of the butterfly represents regeneration. Those who believe in life after death can use this image to represent Doodle after his death (with hopes that he will not be "broken" like he was in life).

3. Similar to the butterfly, Doodle could be represented by the symbol of the phoenix. Again, the phoenix represents rebirth. Given that the phoenix is a fire-bird, this symbolic image would parallel that of the scarlet ibis (which is red as well).